Isolating plug for fixing electric wiring on walls



Feb. 19, 1935. A. HEMFEL 1,992,073

ISOLATING PLUG FOR FIXING ELECTRIC WIRING ON WALLS Patented Feb. 19, 1935 UNITED STATES ISOLATING PLUG FOR FIXING ELECTRIC WIRING ON WALLS Alfred Hempel, Bad Blankenburg, Germany Application February 7, 1934, Serial No. 710,077 In Germany February 6, 1932 5 Claims. (01. 17 3-313) This invention relates to an isolating plug for fixing electric wires on walls, especially to such plugs, in which the wiring is lodged in a groove of the plug and is retained in its position by means of a spring-actuated clamp.

Plugs of this kind hitherto known have the disadvantage that the clamp mustbe lifted contrary to the spring force away from the wall. Such plugs can only be fixed to the wall by means of wood screws, but not by means of nails driven into the wall. In addition the fixing of the known plugs to the wall by means of nails was impossible as they were not provided with a surface which could be struck by a hammer. It is true that plugs are known provided with nails which can be hammered in, but the known plugs of this kind have screwed clamping parts which can easily be lost or become loose.

The object of the invention is to avoid these disadvantages. An essential feature of the new plug lies in the spring-actuated clamp consisting of a hollow cylinder surrounding the carrier for the electric wiring, and adapted to be shifted towards the wall contrary to the spring-action for lodging the electric wiring into the plug. Both the carrier for the wiring and the hollow cylinder surrounding it are made of insulating material. The carrier at one end is rigidly connected to a nail, and at the other end it projectsafter the wiring is lodged in the carrier--beyond theouter end of the hollow cylinder in such a manner that it can easily be struck with a hammer.

In the accompanying drawing two embodiments of the invention are shown, the one in Figs. 1-3, the other in Figs. 4-6.

Fig. 1 is a perspective view of a plug showing the position of the parts before the wiring is inserted into the plug. The hollow cylinder is shown in cross-section.

Fig. 1a shows a perspective view on a larger scale of a part of the hollow cylinder adjacent to the upper rim thereof.

Fig. 2 is a plan view of the plug corresponding to Fig. 1.

Fig. 3 is a perspective view of the plug fixed to the wall after the wire has been inserted.

g is the carrier made of insulating material for the wiring, a is a hollow cylinder surrounding the carrier also made of insulating material. 0 is a projection fixed to the carrier g at its upper end. at is an oblique groove provided in the carrier at the side opposite to the projection c, and serving for lodging the wiring i in position to the plug (see Fig. 3), l is an annular projection provided on theinterior surface of the hollow cylinder a near its upper end. tending through the annular projection Z, the width of which is equal to or greater than that e is a slot exof the projection c. ,f, f are two projections pro- 5 vided on the upper rim of the hollow cylinder a. These two projections lie on both sides of the slot e. h is a groove cut into the upper rim of the hollow cylinder a and the annularprojection l, the width of which is equal to or greater than that of the projection c, and the length of which is less than the height of the annular projection l. b is a helical spring the lower end of which rests upon an annular projection g 1 provided at the lower end of the carrier g, the top end of which spring rests against the annular projection Z of the hollow cylinder :1. o is a nail rigidly connected to the carrier g. This nail is preferably made of triangular cross section, in order to prevent any torsion after being driven into the wall.

In the position shown in Fig. 1 the hollow cylinder a is pressed against the projection c lying in the slot h. For lodging a wiring into the groove d the hollow cylinder a must be shifted towards the wall, until the upper rim of the cylinder lies underneath the lowest point of the groove (1. After the wiring has been lodged into the groove d, the hollow cylinder a is released by hand and is now pressed upwards by the spring b, until the upper rim of the hollow cylinder abuts against the wire 1. The two projections I then he on the one side of the wire i immediately adjacent thereto preventing the hollow cylinder from being turned (see Fig. 3). For releasing the conducting wire i and for removing it, the hollow cylinder a must be shifted towards the wall until its upper rim lies under the groove d.

For dismounting the plug shown in Fig. 1, the hollow cylinder must be moved towards the wall until the projection 0 lies above the upper rim of the hollow cylinder a. The hollow cylinder a can then be freely rotated. Upon a rotary movement to the extent of 180 the slot 6 then lies under the projection c, and allows the hollow cylinder a to be drawn upwards to its entire length, and thus to be removed.

Fig. 4 is a perspective view of another embodiment of a plug according to the invention, a part of the hollow cylinder being shown in cross section. The figure shows the position of the plug and its parts before the wiring is attached thereto.

Fig. 5 is a plan view of the plug shown in Fig. 4.

Fig. 6 is a perspective view of the same plug after the wiring has been lodged therein.

In the embodiment shown in Figs. 4-6 the hollow cylinder is made of two parts a, a which are held together by a circular spring m. The one half a of the hollow cylinder is provided with a projection n which engages with a corresponding groove of the other half a. The top end of the carrier 0 is provided with two projections 9 and g against which the hollow cylinder a a rests, when the parts are in the position shown in Fig. 4.

What I claim is:

1. In an isolating plug for fixing electric wires on walls, in which plug the wiring is lodged in a groove and is retained in its position by means of a spring-actuated clamp, the spring actuated clamp consisting of a hollow cylinder made of insulating material, a carrier for the electric wiring made of insulating material surrounded by the said hollow cylinder, the said hollow cylinder being adapted for movement towards the wall contrary to the action of a spring, the said spring being adapted to abut at its lower end against an annular projection provided on the bottom end of the carrier, its top end abutting against an annular projection provided at the top end of the inner surface of the hollow cylinder, a nail rigidly connected with the said carrier, a groove provided in the said carrier and adapted to take up the wiring,

means for retaining the hollow cylinder in its upper position, means for preventing the hollow cylinder from being rotated after the wiring has been inserted into the plug, and means for allowing the rotation after the wiring has been taken off.

2. In an isolating plug according to claim 1 the means for retaining the said hollow cylinder in its upper position consisting of a projection fixed on the said carrier at its upper end, and of a groove provided in the upper rim of the said hollow cylinder and adapted to engage with the said projection.

3. In an isolating plug according to claim 1 a groove cut into the therein referred to annular projection provided at the upper end of the inner surface of the said hollow cylinder, the width or which groove being equal to or greater than that of the said projection c.

4. In an isolating plug according to claim 1 two projections on the front face of the upper rim of the said hollow cylinder lying on both sides of the said groove and adapted to abut against one side of the wiring when this is inserted into the plug.

5. In an isolating plug according to claim 1 the said hollow cylinder consisting of two half cylinders, and a circular spring adapted to hold the said two half cylinders together.

ALFRED HEMPEL. 

